In a factory for implementing the IC manufacturing method (hereafter called, IC manufacturing factory), the external dimensions (foot print) of the substrate processing apparatus and in particular the width of the substrate processing apparatus must usually be kept small in order to install and array many substrate processing apparatus within the clean room.
In order to restrict the foot print by installing multiple substrate processing apparatus to the side and adjacent to each other in the IC manufacturing factory, the IC manufacturing factory must be designed so that maintenance (service and inspection tasks) of the substrate processing apparatus is not performed from the side (side-maintenance-free).
However, a natural oxide film that might be formed on the wafer is a factor in causing lower quality and reliability of the product (IC) as well as a drop in the production yield in the IC manufacturing method.
As substrate processing apparatus of this type of the prior art, the substrate processing apparatus using the load lock system (a system where the processing chamber and the carry-in/out chamber (standby chamber) are separated using a separator valve such as a gate valve, the inflow of air to the processing chamber is prevented, and the process is stabilized by reducing external disturbances such as pressure and temperature.) has been developed.
Substrate processing apparatus using the load lock system of the prior art to meet the above needs is the substrate processing apparatus of the type described next (See for example, patent document 1.).
The carry-in/out chamber (hereafter called the load lock chamber) and the transfer chamber separated from the processing chamber by the gate valve, are provided in order within the case from the rear side. A door valve for maintenance is installed on the rear side of the load lock chamber and a wafer-carry gate valve is installed on the front side of the load lock chamber. The valve opening of the gate valve is set to a size large enough to allow a person to pass through and all maintenance tasks can be performed from the front side or the rear side.                Patent Document 1: Japanese Patent Non-examined Publication No. 2000-269299        